306 REPORT OF THE HARVARD AFRICAN EXPEDITION 
blood vessels. He believes that the presence or absence of this typical modi- 
fication of the vessels is the point that allows one to decide which of the two 
diseases is present, and it is true in the cases of syphilitic condylomata and 
papillary lesions of framboesia as well as in the later lesions of these two dis- 
eases. 
In some respects the descriptions given by Hallenberger correspond with 
our own observations, already outlined in this chapter. We, however, have 
not observed such clear-cut and characteristic appearances as he sometimes 
outlines, either in our study of the early or late lesions of yaws. Unfortunately, 
all syphilitic tissues do not show the classical, typical modification of the blood 
vessels, and we believe that there is often considerably greater variation in the 
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No. 232. — Case 404. Photomicrograph showing downgrowth of epithelium, condition 
of blood vessels, and infiltration in corium about them 

pathological changes in different cases, so that in many instances, particularly in 
the tertiary stages, the syphilitic lesions cannot be distinguished from the fram- 
boesial ones by the histopathological appearances. Hallenberger himself has ree- 
ognized these difficulties, and, in fact, points out that gummatous lesions of the two 
affections may be indistinguishable from one another.! 
1 While this Report was in press, Howard Fox (Jour. Trop. Med. and Hygiene (1930) XX XIII, 26) 
has reported upon the histological examination of two cases of secondary and two of tertiary yaws, the 
microscopical examinations of which were made by Highman. He states that in one section giant cells 
were found, in another the vascular changes roughly suggested syphilis, and in all the intima and media 
were swollen. No productive inflammation, however, was found in the vessels as in syphilis. (The 
histological changes in rabbits are referred to on page 286, Footnote 4, of this Report.) 
